


The Great Change

by Natron77



Series: Lewdnessday Tales [5]
Category: Original Work
Genre: Alternate Universe, Centaur, Explicit Sexual Content, F/M, Modern Era, Original Character(s), Transformation
Language: English
Status: In-Progress
Published: 2018-01-13
Updated: 2018-01-17
Packaged: 2019-03-04 08:46:55
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 8,121
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13360878
Author URL: https://archiveofourown.org/users/Natron77/pseuds/Natron77
Summary: Life on Earth would never be the same. All over the world, 15% of humanity suddenly became part animal. From centaurs to mermaids, people of all walks of life found themselves transformed overnight.In addition to the stress of the crazy new world, many relationships struggled, particularly in bed.





	1. My Girlfriend's a Centaur Now? Part1

It should have been a day like any other, but something happened the night before that changed the world forever.

“Serah, why didn’t you wake me up?” a man grumbled sleepily as he sat up in bed. His name was Shoto and he had short black hair, warm brown eyes, and a slightly round face. The clock said it was 8am, meaning he had only a few minutes to get ready and leave for work. The Tokyo commute was hell, but he’d found a route that got him there on time as long as he left the apartment by 8:15.

Shoto turned and saw his girlfriend across the bed. She was always an early riser and usually woke him every morning with a cheerful kiss. The fact that she hadn’t done so this morning, even though she was awake and right there in the bedroom, suggested something was wrong.

The dumbfounded expression on her face proved it.

She was standing at the side of the tall bed, staring down at her legs. Her shoulder-length brunette hair was a total mess as if she hadn’t touched it since she awoke, but that would have been an hour prior. She was wearing a loose pink shirt, worn thin by how often she had worn it to bed. It did little to hide her pleasantly perky breasts.

“Serah? Are you okay?” Shoto asked. He quickly got out of bed, wearing just some black boxer briefs, and walked around to her side. As he rounded the corner of the waist-high bed, his gaze involuntarily followed hers and he saw what she was staring at. He instantly knew that Serah was _not_ okay.

For some reason, her purple panties had been reduced to just a waistband and some tattered cloth. Below that, where her bare legs should have been, there was a bunch of brown fur. The fur covered two spindly legs with knobby knees, ending in two dark and solid things that definitely seemed to be hooves.

_Hooves? What?_ It was all Shoto could think. And judging by Serah’s face and her frozen state, it was all that _she_ could think too. She’d been stuck in a loop, thinking it over and over for possibly as long as an hour.

But then he noticed what was behind her. From just above her hips, more of that brown fur extended backwards for several feet. Shoto stepped sideways and saw it for what it really was: the body of a horse, complete with four legs.

His mind raced. It was filled with dozens of questions, but the answers weren’t actually important. What was important was the woman in front of him, the love of his life, and how she was doing. Not only did she likely have some of the same questions he did, but she had to deal the added impact of this mysterious horse body being _her_ body.

She was still so transfixed by the legs that she hadn’t noticed the rest yet. Shoto sprung into action, wanting to soften the blow before that little revelation crashed in on Serah like a stampede. He stepped up in front of Serah and wrapped her in a tight hug. In the back of his mind, he was pleased to note that she was still the same height, about two inches shorter than him.

“Serah, I don’t understand what happened, but I will be here with you through it. Maybe this is a dream, or maybe it’s real, but we need to stay calm and collected.”

“My legs,” Serah finally said, her voice soft and sweet and innocent as always. Extra-innocent in fact, given her ignorance of the full scope of her issue.

“Yes, they seem to have changed,” he replied. “I need you to take a deep breath for me, okay?”

Serah nodded and looked into Shoto’s brown eyes. Her green ones were panicked and wide.

Only after she finished a deep and slow breath, Shoto said, “Other parts of you seem to have changed too. Stay calm, but look at your butt.”

A glint of fear crept into her eyes, but she stayed calm and turned her head slowly. She didn’t need to turn far to see what had happened. Several feet of sturdy brown body extended horizontally from her lower back, and a long brunette tail stuck out at the end. The surprise of seeing it sent the tail twitching in perfect sync, and sent its sensations directly to her brain. That was the proof she needed to believe that the body was actually hers.

“I’m a horse?” she asked. Always a level headed woman, she quickly corrected herself, “No, a centaur.”

Then she reached up and pinched herself on the cheek, hard enough to really hurt and likely bruise. “Not dreaming,” she mumbled.

Shoto grabbed her hand before she could hurt herself more. “Not dreaming,” he confirmed. Then he stepped back and reached for his phone, which was charging on the headboard of their bed. “I’m calling out from work to help you. While I do that, can you make us some tea? I think it would be good for you to do something comforting and familiar.”

Serah nodded slowly, then pivoted awkwardly to exit the small bedroom, her hooves clopping softly on the floor. While the body was brand new, she somehow already knew how to use it pretty well.

“And keep the blinds closed. I feel like we should keep this quiet for now,” Shoto added.

* * *

Keeping it quiet was totally unnecessary. All across the world, people were hiding in their homes, racing to hospitals, and in some cases rioting. Religious nuts called it a sign of the apocalypse, politicians called it ‘The most trying event in humanity's history’, and newscasters babbled uselessly about what might have caused it.

Regardless of the cause, the results were clear: the night before, as midnight hit the international date line, a transformation began in a random portion of the human population. Any selected people who were awake at the time felt unbearably ill and tired until they went to sleep. All the affected people were fundamentally changed by the time they next awoke.

In total, fifteen percent of all humans had become part animal. They gained things like tails and fur, wings and antennae, and sometimes even extra arms and legs. In most cases, their new appearances matched those of famous mythical creatures, but some were brand new creatures.

Within 24 hours, the public had started calling it the ‘Great Change’, and within another day, all major world governments had banded together to protect the Changed people. Some extremist countries tried to kill their Changed residents, but larger countries with military might came to their rescue, liberating animal-people by the thousands.

Japan was the one of the more receptive countries. By the third day, the government had placed dedicated experts in designated hospitals all over the country, ready to help Changed people understand their new bodies. Serah and Shoto visited one of those hospitals, and that’s how they came to meet Dr. Akido.

Dr. Akido was a shorter woman, with bob-cut black hair and an unthreatening demeanor that didn’t dampen her air of aloof intelligence. She had mentioned offhand that she used to be a farm veterinarian before becoming a human physician, and that it was likely a factor in the government selecting her for the new role as a Great Change specialist.

After meeting with Serah in private for over an hour, she greeted Shoto in the waiting room and beckoned him to follow her. As they walked, she explained, “Serah didn’t want to be here for this part, so she’s getting dressed in another room.”

Shoto’s step faltered slightly at that ominous phrasing. “What is ‘this part’ exactly?” he asked.

“Where I explain to _you_ how her body works now. I’ve explained it all to her, and I offered to let her tell you herself…” she said, trailing off.

“But she was too embarrassed,” Shoto finished. “That’s just like her.” He smiled. It was good to see that some things hadn’t changed at all.

Dr. Akido smiled and nodded, then directed Shoto into an exam room.

When he stepped inside he immediately noticed the familiar smell of his girlfriend’s perfume, but there also a deeper animal smell that he vaguely recognized. He had caught whiffs of it from time to time over the previous couple days. He realized now that it was the smell of Serah’s fur-covered half, and that she had been trying to hide it with perfume.

The doctor noticed his sniffing and said, “You’ll get used to the scent, and it will lessen once she starts using appropriate coat-care products.”

Shoto glanced around the room in an effort to distract himself from the strange topic. He quickly noticed a long glove in the trash can. It was shoulder-length and it looked wet. He immediately tried to push _that_ out of mind.

Fortunately, Dr. Akido directed his attention to a diagram that was projected on the wall. It was a simple handmade drawing, but it was very neat and detailed. The diagram clearly depicted a centaur and its internal structure.

“When the Change hit, several of Serah’s organs moved around.” She pointed with a stick at the upper body of the centaur silhouette. “As you can see here, her heart is still in her upper rib cage, but it is much larger, in order to serve her larger body. And down here, the lower rib cage in her so-called ‘horse’ part is where her new and more powerful lungs are. Keep that in mind if you ever have to perform the Heimlich Maneuver.”

“So her throat is…” Shoto started.

“Her esophagus is quite long, yes. Like a giraffe in some respects, but better protected by the rest of her upper body.” She moved her pointer to the upper body’s belly area. “Most of her other organs stayed put, though some got a bit bigger. The biggest remaining changes are in the digestive and reproductive systems.”

The word ‘reproductive’ caught Shoto’s attention. Sexual desire aside, Shoto hoped to have kids someday, and he’d been secretly worried that the Change would affect that. To his dismay, Dr. Akido quickly shot down any remaining hope.

“Her reproductive organs here”—she tapped on the upper body’s belly area again—“appear to have shut down. They are all still present, but her ovaries are entirely off. Since her urinary tract also moved to the lower body, the entire vaginal area is pretty much cosmetic at this point.”

She winked and added, “Though she did say she still feels pleasure there.”

“Wait,” Shoto said slowly. “If her urinary system moved, then—”

“Yep, she’s got a ‘horse’ vagina too. The entire reproductive system, even. So far, it seems that all Changed quadrupeds got this duplication. If the Great Change was done by a conscious being, they were kind to not fully take away those people’s previous genitals.”

She smiled a weary and sad smile and added, “And before you ask, we have no idea if the new reproductive system is functional _or_ compatible with human sperm. That research is still in progress.”

Shoto nodded firmly. “I understand. In fact, I’m surprised with how much you already know.”

“There’s nothing quite like a global calamity to get people working together and sharing information,” Dr. Akido said with grin. She was clearly excited by the new scientific prospects coming in the near future.

“Oh, and before we move on, her large intestine and anus moved to the lower body as well. Modern toilets weren’t designed for horse butts, so I’ve recommended that she stick to traditional Japanese squat-style toilets whenever possible.”

Shoto blushed at that blunt statement, but nodded.

After a couple more brief anatomy lessons, Dr. Akido escorted Shoto back to the waiting room where Serah was already waiting. She galloped into his arms and hugged him tight. He couldn’t pick her up in a bear hug anymore, but she was still the same Serah he’d fallen in love with.

After the hug turned into a kiss that almost turned indecent, Shoto turned to Dr. Akido and said, “Thank you, doctor, for everything.”

“No problem. If you have any questions or issues in the future, please call me. I’m here to help you, and the government can use your experiences to help others in similar situations.”

Then she put a kind hand on Serah’s shoulder and said, “Take care of each other.” The words carried the unspoken message that their troubles weren’t over just yet.

* * *

Serah’s day to day life didn’t change as much as she had expected. After a few days of calling in sick and hiding at home, she finally worked up the courage to return to work, only to find that her supervisor had become a literal merman, gills and all. He refused to let the Change affect how anyone was treated around the office, and her mood was lifted when she saw that he was still respected by his peers in his new form. In some ways, he was even worse off than Serah, particularly in terms of mobility.

Her best friend at work, a plain little woman named Deci, even wished that _she_ had been changed. “It could have been my chance to stand out. No one notices human Deci, but catgirl Deci, or butterfly Deci, or even shark Deci… They’d _have_ to pay attention then!”

“It isn’t that great, you know. I don’t even want the attention, and I can’t fit in most cars anymore, or use most bathrooms. And my wardrobe is mostly useless now. Every skirt and dress, all my cute socks and shoes…”

Right after the change, Serah had made a simple skirt to fit her new body, and modified some of her underwear to fit each of her _two_ private areas, but her selection of clothes was still very small. She frowned deeply and thought to herself, _I was wearing my favorite panties when I Changed, and they were totally destroyed_.

“Can I have them?” Deci brazenly asked. “If you don’t want them anymore, that is.”

Serah was weirded out by the question until she realized Deci wasn’t talking about the panties. She answered, “I’m going to try to tailor the dresses and socks into something I can wear, but you can have the shoes, I guess.” Serah’s feet were the same size as Deci’s, or at least they had been, before the Change.

“Aww, you’re the best, Serah. Can I swing by tonight and pick ‘em up?”

“Uh, I have plans, sorry,” Serah mumbled and immediately turned beet red. She was terrible at hiding her feelings, and she was thinking of the romantic evening that she and Shoto had planned.

Deci knew all Serah’s tells, although the adorably twitching tail was a fun new one. She smiled and said, “Say no more. Good luck, Serah.”

_Thanks. I’ll need it,_ Serah thought. She would never say this aloud, but she’d had sex several times since the Change, and never once was she able to reach orgasm. She was hoping the extra romance planned for that night would make a difference.

* * *

Shoto left work early to get home before Serah and prepare an elaborate dinner. He was using a lot of fresh veggies, which she enjoyed more since the Change, and he’d even bought a very nice bottle of wine.

He was hoping tonight would be the night for Serah. Their relationship had always been rather physical and sexual, and he was worried that the Change had hurt Serah’s self-confidence. At the very least, the stress of it all wasn’t doing her libido any favors.

He still loved her, and he loved her body. The Great Change didn’t affect that as much as he’d expected. He had cooed and coaxed her into some pleasurable sex, but never got her to an orgasm. _But tonight, I’m really gonna lavish love on her ‘til she finally comes!_

Their dinner date went perfectly, and Serah quickly got into a very frisky mood. While Shoto was attempting to serve dessert, she nuzzled up to him and whispered, “I’ve had enough food. I want something else in me.”

Shoto blinked in surprise. That had been incredibly risque for the easily-embarrassed Serah. He set the bowl of berries and cream down and said, “Alright, honey. Shall we retreat to the bedroom?”

She pressed her body against him and started pushing him backwards, toward the couch. With her four legs and extra mass, she easily overpowered him. “How about here?” she asked meekly.

While her words were restrained, her hands were not. She was already undoing the buttons on Shoto’s dress shirt. By the time she got him backed against the couch, she even had his belt undone.

They each undressed the other until they were both entirely naked. Serah had even removed the underwear on her back half, lest they get wet. Then Serah pushed Shoto down onto the couch and straddled him with her front legs. Her hindquarters were firmly planted on the ground, giving her a lot of leverage and control of the position.

“You are beautiful,” Shoto said, then he kissed her before she could doubt the words or respond. The kiss turned into an open-mouthed one, then he added his tongue, darting it along the bottom of her upper lip.

She moaned into it, so he kept going and he added his hands. They slid over her back, her shoulders, her breasts, and down to her hips. Other than the soft brown fur there and the lack of a squeezable booty nearby, her wide hips were very similar to before. Then his hands wandered to her belly and crotch, which were totally unchanged.

Shoto was about to step things up with his fingers on her pussy when Serah took charge again. She grabbed his erect penis and pressed it against her already-wet opening. After a bit of wonderful teasing up and down along the slick slit, she popped it inside.

Shoto gasped. His cock felt amazing as it was enveloped by her bare walls. If there was a silver lining in the Great Change, it was that he could now ride bareback, so to speak, with no need for any form of birth control.

_Alright_ , he thought, _if she’s running that show, I’ll help her out up here._ He cupped a perky and pillowy breast in his hand and brought his mouth to it. After a few light and testing licks, he applied some suction directly on the nipple. As Serah bounced up and down on his cock, the nipple was tugged in time in a way she loved. But he also had another trick to apply.

He opened the right side of his mouth and breathed in sharply, pulling cool air across Serah’s wet nipple while he licked up and down quickly. The result was a blast of several sensations all at once. Serah’s body stiffened in a way that screamed, ‘Keep going!’ so he did. And he added massaging pressure on her lower back, pushing in time with their synchronized hip motion.

The combination of his intense focus on the task at hand and the wine in his system let him keep going without fear of coming too soon. Sometimes the dampening effect alcohol had on his ability to get off could be annoying, but it was serving him well this time.

Meanwhile, Serah’s hands were between their bodies, her fingers working furiously at her clitoris. She occasionally gave herself a hand in that way and before the Change it had always got her quickly to orgasm.

This time, it did not. They kept at it for another 15 minutes, trying every pleasurable variation they could, until their bodies ached and their genitals could take no more. But she never got there. Shoto also went without orgasm, since his failure to get Serah off was a substantial bummer.

Panting, their movements came to a stop. Shoto held Serah close and whispered, “I love you.”

“I love you too,” she replied, but there was sadness in her voice.

“I think we should…” he started, but he trailed off, not sure that he wanted to say anything just yet.

“…see the doctor again,” Serah finished.

He nodded and pressed his forehead to hers. “Yeah.”

* * *

They had to wait several days for an appointment with Dr Akido, since it would be their second visit and it wasn’t an emergency. Great Change specialists were in very high demand, after all. When the appointment finally arrived, Serah didn’t delay in telling the doctor what the problem was.

“I can’t orgasm any more,” she said flatly.

Shoto, seated next to her, blushed and looked at the floor.

Serah continued, “We’ve tried a bunch of things that used to be reliable ways to get me off. They still feel great, but I just can’t reach… uh, _it_.”

Dr Akido nodded as she listened, then said, “I can’t go into specifics due to privacy laws, but I’ve heard a similar thing from another patient who got a second set of genitals in the Great Change. I have a theory about the cause, but I’d like to confirm it via a test.”

Shoto and Serah shared a glance. “Okay,” Serah said.

“First, I assume you’ve only been having sex with your human side?”

The couple nodded shyly.

“I figured as much. Now, I need to ask Serah some personal preference questions. Shoto, can you step out for a minute?”

After Shoto returned to the waiting room, Dr Akido asked Serah, “Regarding your sex life before the Change, what kind of genital stimulation gave you the most pleasure: clitoral; vaginal, including girth; or cervical, meaning depth?”

Shyly, Serah whispered, “I guess all three? My favorite toy was a large rabbit-style vibrator…”

The doctor nodded, not casting any judgement on Serah’s choice of sex toy. “Alright, I’m gonna prescribe you a very specific tool. You’ll have to custom order it, but since it is a prescription your insurance will cover it, as long as you order from a place that knows how to bill it properly.”

“Okay…” Serah said as Dr Akido scribbled something on a piece of paper.

The doctor took a deep breath and said, “Take your rabbit vibrator to this shop, and give them these measurements. They’ll make a scaled-up replica for you to try out. Don’t force it, but the next time the mood strikes, use the new tool while you have sex normally. Then report back to me.”

Serah took the paper and read an address labeled ‘Tokyo Reproductive Recuperation’. There was a list of numbers after that: measurements for her new sex toy. She read the measurements and her jaw dropped. “No way. These numbers are huge!”

Dr Akido nodded and shrugged. “Yep, that’s how large you are down there now. I went with the baseline measurements, so this may even be a bit small if you really like to feel stretched.”

Blushing brightly, Serah said, “Oh, alright. I think I’ll be okay…”

* * *

Serah, with no small amount of embarrassment, ordered her new toy that day. However, the shop needed a couple days to make it. When it was finally ready for pickup, the idea of it excited her enough that she wanted to try it that very night.

When she got home with her discreet and surprisingly heavy box, she opened it and marveled at the massive toy. It was shaped similar to her favorite rabbit-style vibrator, but larger in every dimension. Similarly, its motor was substantially bigger than that of the vibrator it had been modeled after, so standard batteries simply couldn’t output enough power. Instead, it had a power cord so it could be plugged directly into the wall. Thankfully, they had an extension cord around the house so that the toy could reach any part of their bed.

At first, Serah was too embarrassed to let Shoto put the new vibrator in her lower half, so she tried it herself. It didn’t take long for her to admit that the angle was too awkward and uncomfortable to reach properly. Eventually, she yielded and let Shoto handle it.

“Don’t look,” she begged, covering her face with both hands.

“I have to look, honey, so I can tell what I’m doing,” he said, but secretly, he really wanted to look. He wanted to see all the new and erotic parts of his girlfriend’s beautiful, if unusual, body.

Serah distracted herself by playing with her breasts and pussy, or at least her front one, in order to stay aroused. Meanwhile, Shoto maneuvered the hefty toy into place. It was as long as his forearm and as big around as his fist. He tried very hard to not compare it to his own manhood, which was average by human standards but couldn’t compete next to that super-sized dildo.

Surprisingly, it slid in easily, suggesting that it was potentially too _small_. While back there, Shoto cast a couple admiring glances at Serah’s pussy and ass, and found them wonderfully intriguing. He’d never been attracted to horse anatomy, but this was his beloved Serah, and now she had new exotic and sensual places. He made a mental note to ask to go exploring a little some time, when Serah was in a good mood.

Serah felt the toy enter and she definitely enjoyed the feeling of fullness, but it wasn’t all that strong on pleasure. That is, until the toy turned on. The instant Shoto switched the vibrator on, Serah was slammed with pleasure she’d never felt before. Nerve pathways she’d never used before fired into action, sending brand-new sensations to her brain.

The toy narrowed before its extra wide base, so it stayed firmly inside of Serah’s pussy. Shoto crawled on the bed, around to her front. He was already aroused and erect and ready for fun, but Serah shivered and held up a hand, palm out. “H-hold on. I need t-to, uh, get used to—” She took a quivering breath. “U-used to this.”

At first, Serah thought she’d orgasm from the toy alone, but the feeling faded as she got accustomed to all the new sensation. She waved Shoto over and sat down on his lap, face to face.

He guided himself into her vagina, then kissed her sweetly on the lips. He didn’t get a chance to do much else.

Almost immediately, the erotic thought and the physical sensation of being filled in both pussies set her off. She grabbed Shoto tight with both arms, let out a sultry moan, and had her first orgasm of the night. Her first since the Great Change had hit the world over a month prior.

Thankfully, Shoto was still hard and Serah was capable of multiple orgasms. The toy in her lower body was nice and secure, leaving all her attention on her actions up front. Her strong front legs controlled the thrusting speed to great effect while Shoto had easy access to her chest.

By the time Shoto couldn’t hold out anymore and finally came, Serah had gone at least seven times. For another few minutes afterward, Serah left the toy and dick inside and just savored the feeling of fullness in both vaginas.

Eventually, Shoto got too soft and slipped out, making a bit of a mess. While Serah wiped it up with tissues, she asked, “Can you please turn that thing off? It’s getting to be too much…”

Shoto scooted out from under Serah to get to the toy, making a mental note to buy one of those remote-control outlet plugs made for lamps so that they could control the toy while it was far away. That seemed like a very minor problem to have, all things considered.


	2. My Girlfriend's a Centaur Now? Part2

A few months ago, the Great Change caused 15% of humanity to become partially animal. People all over the world gained features for animals, ranging from horse to butterfly, through the unexplained transformations. Society was forced to adapt as celebrities, politicians, parents, and even children transformed and needed special accommodations.

The area where society proved least adaptable was the Changed people’s sex lives. The prudish public refused to approach the topic and people suffered as a result. Even the couples who visited doctors and sought out creative solutions on their own ran into a new problem eventually: mating season.

Estrus, rutting season, being in heat. There are many words for mating seasons but the effect is largely the same: at certain times of year, the animal gets uncontrollably aroused and literally _needs_ sex. For Changed people this was incredibly disruptive, requiring people to take time off work, or in some cases, driving them to extreme behavior to find sexual relief.

During Serah’s estrus, she was beyond horny. She had to call out of work because she was wet and aroused all day. Every waking instant was like torture, with every cell in her body crying out. She tried to satisfy herself through masterbation, but it wasn’t enough.

The second Shoto got home from work, she literally begged, “Fuck me, Shoto. I need it. I need your cock and every toy in the house in me! Maybe that will let me come and end this nightmare.”

Shoto wanted to make a quip about the word night-’mare’ and thought better of it. Serah was normally receptive to his dumb jokes, even at her expense, but she was not in a normal mood. Every instant she wasn’t having sex, she was annoyed or even angry. And sex was its own exercise in frustrating futility: she hadn’t been able to orgasm for two weeks, despite trying several times every day.

Shoto was chugging protein shakes and vitamins like mad, trying to keep up with his ravenous centaur girlfriend, but it was starting to take a toll on him. Already, Serah had bruised his thighs when she’d dropped her full weight on him in a moment of missed-orgasm despair. If that happened again in a way that hurt his dick, it was all over. He was worried about whether their relationship could withstand the stress that Serah’s estrus was putting on it.

Shoto took a long, slow breath, then said, “Serah, I have an idea that should help you. But it’s a bit unusual.”

“Oh? What is it?” She was struggling mightily to act only mildly interested. Under the surface she was boiling with desire and nervous energy.

“We haven’t tried anal. Maybe three points of contact will be enough to get you off.”

Serah nodded. Of course she’d thought of that days ago, but she had been worried that Shoto would be grossed out and she knew that she couldn’t reach her ass by herself.

Shoto said, “The way I see it, we could attach a dildo to a wall to use on your butt, but that seems really tricky…” Shoto was thinking that Serah’s size and lack of visibility would be too prohibitive.

Serah nodded again, slowly. She’d actually tried that herself while Shoto was at work but she’d been unable get the positioning right. With every drop of her willpower, she calmly said, “Yeah, that doesn’t seem like it’d work.”

“Or I can be in the back. I don’t know if that weirds you out but I’m willing it try it if you are.” He blushed a little and broke eye contact, then said, “I think it could be fun…”

Serah’s eyes lit up and her mouth started to water. She’d been worried for nothing. “We have a deal. Get back there,” she said with surprising force. She was already stripping off her clothes, not that she was wearing much. With her heat in effect, anything pressing on her crotch or nipples was torture.

While Shoto clumsily undressed, Serah plugged the toy they’d nicknamed the “Big One” into the remote control outlet, which was currently powered off. All the lower settings were worthless when she was in this state so she flipped the toy to its max setting in preparation. She took the remote in one hand and her favorite regular rabbit vibe in the other.

Without waiting for Shoto, she climbed on the bed, turn turned the smaller vibrator on and slipped it in. _As soon as he gets his lazy ass in gear and gets the Big One in me, I’m turning it on and grabbing my tits. It isn’t as good as when Shoto sucks on ‘em, but beggars can’t be choosers._

“Uh, I was thinking I’d use a condom, for cleanliness reasons,” Shoto said cautiously.

“Sure, whatever. Just get in me already,” Serah snapped. Then with a bit more restraint, she added, “Actually, put the Big One in first.”

Shoto grabbed the toy and lined it up with her gaping and dripping pussy. The size of that toy always made him feel inadequate but he knew that no human cock, not even a pornstar’s, was going to satisfy Serah’s horse-sized slit.

He pushed the massive rubber cock into Serah but before he could even get the rabbit part lined up with her clit, she turned it on. On its max setting, it was like trying to hold a live wire and his hands quickly started to tingle. If he didn’t get it lined up soon, they’d go numb.

Thankfully, he got it aligned and gave it a solid push into place. It stopped only when the rabbit’s base hit her mound. Her cervix must have been deeper still. _Maybe that’s part of her problem,_ he thought. _When she’s this aroused, her cervix moves too far back_

The toy was slightly thinner just before the base than it was around the center so it stayed inside Serah without help. While that feature was normally very necessary, since neither of them could reach it in their standard positions, this time Shoto would be back there to realign it as needed. But first, he had something else to do.

With shaking hands, he opened a condom wrapper and slid the condom on his very erect dick. The idea of finally trying anal had him aroused, and Serah’s eagerness was a major turn-on too Then he gently pulled Serah’s new brunette tail out of the way.

“Mmm,” Serah moaned at the slight tug. “Do more of that, once you’re in.”

“You got it,” Shoto replied distractedly. His eyes were glued to his goal: the round and puckered entrance of Serah’s ass, just above the stuffed and vibrating chasm of her pussy. He started to line himself up with it but he remembered something important: unlike her pussy, which was slick 24/7 lately, her ass needed lube.

He grabbed a bottle of lube and squirted some directly on his wrapped dick. He thought it might be too much, but he’d heard that more was better in these cases. He spread it around with one hand then wiped the hand off on the towel they’d already placed on the bed.

Wrapped and lubed and ready to go, Shoto finally pressed the tip of his cock to the ring of Serah’s asshole. She twitched at the cold sensation then lifted her butt into it. He knew her large horse anatomy could handle much bigger than him, but it was hard to overcome the desire to take it safe and slow. What she said next helped.

“Stick it in me, Shoto. I know you’ve wanted this since you stared at it when you first put the Big One in me. My ass wants your cock just as much, if not more.” She turned her upper body around to look him in the eye. When he finally met her gaze, she added, “And I know I’ve been a bitch lately because of this estrus, but I really love you.”

“I love you too,” he replied, then he pushed it inside.

It was tight. Tighter than he’d expected, but just because her ass was big didn’t mean it had to be loose. And it felt great. He could even feel the Big One’s vibrations through Serah’s body. He thanked god that the condom was dampening the sensations a bit or he might have gone off early.

“OOooh,” Serah moaned. “You feel so _big_ , Shoto.”

That was exactly what Shoto needed to hear after his humbling comparison to the Big One. With that erotic thought fanning his flames, he started to thrust. He slid the length of his cock in and out in measured movements, using the slight bulge of his cockhead as a guideline, stopping just before slipping out. All the while, he could feel the tense tightness of her ass squeezing down on him.

Once he got into a rhythm, he was able to focus on the task at hand: getting Serah off by any means necessary. And his current ‘means’ included his two free hands. He grabbed her tail near the base and gave a testing tug.

“Yes, yes!” Serah called out, She was looking away but her whole upper body was flushed with excitement. She had one hand on her vibrator, grinding it into her human pussy, and the other on her right breast. Her breasts were normally modest C cups but since estrus had hit they’d swollen to Ds or even Es.

And the nipples had gotten _sensitive_. She was pinching one lightly between her fingers and rolling in gently, yet the sensation was nearly enough to be painful. She pressed down against her chest and found that the breast itself had also gotten touchy in a way that felt simultaneously uncomfortable and amazing.

Meanwhile, Shoto had hit a groove and was capitalizing on it. The thought of fucking his girlfriend in the ass while a genuinely massive dildo filled her pussy was enough to keep his engines running at full blast. But adding the fact that she had another dildo in her other pussy and she was going wild on her breasts… that had sent him straight to heaven.

He tugged her tail in time with each thrust and grabbed her flank with his other hand. She had soft brown fur all over her lower body and he really loved to touch it, but Serah was embarrassed and usually kept it covered up. He started to massage her hip in wide, circular motions, until he noticed something interesting: each time he got near her ass, she tightened down delightfully on his cock.

With that in mind, Shoto’s hand migrated further back until his thumb made a teasing pass right near Serah’s occupied asshole. As he’d suspected, each brush sent her sphincter muscles into tiny adorable spasms. He was worried that it might be too distracting for Serah, until she mumbled to keep going.

“You got it, honey,” he said as he switched focus a bit. He aligned all of his activities onto a single cadence, timing everything along with his thrusts. On each plunge, he tugged her tail up and away and slid his thumb on one side of her ass and his index finger along the other. He was even able to stack his hands so they moved together like a totem pole of synchronized sexual pleasure.

“Yes, c’mon, fuck, yes!” Serah called out with increasing volume as she got closer to orgasm than she’d been in weeks. “Harder, Shoto. Fuck me _hard._ ”

As commanded, he pulled back as far as he could and slammed balls-deep back in. In fact, his balls slapped hard against her taint in a way that he enjoyed in the heat of the moment but would likely regret later. They were also touching the base of the furiously vibrating Big One so staying there wasn’t an option. Not that he wanted to. He wanted to thrust harder and faster until Serah came so hard that this estrus nightmare was blown out of her body like an exorcised demon.

Again and again he pulled back and slammed in, smashing his hips against her firm and muscular flank. There was no room for his hands in that melee so he kept one on her tail and withdrew the other. Then in a spur of the moment decision, he winded it back and slapped her on the flank, hard.

Every muscle in Serah’s body clenched in surprise. It was very lucky that she was kneeling on all four knees, because her back legs tried to kick. Instead, she just bucked up a bit, pushing Shoto even harder against her punished ass.

That pushed him over the edge and he couldn’t hold it in any longer. “I’m gonna come, Serah. I’m cumming in your ass!” With that warning, he bottomed out inside her, grabbed tightly into the meat of her flank with both hands, and let loose.

His mind went white as blast after blast pumped out of him, flooding his body with endorphins and filling the condom with cum. On some faint level of consciousness, far removed from reality, he wished that he hadn’t used a condom so he could have painted her insides with his seed.

Fortunately, the mental and physical stimulation of Shoto’s frantic orgasm, along with the veritable assault on nearly every erogenous zone on Serah's body, finally got her off. Like being shoved from behind over a massive chasm, she cleared the previously impassable gap and fell into the absolute bliss of orgasm. “Fuck yes!” she screamed in celebration.

At first, it was a normal orgasm, with wonderful endorphins crashing into her mind and body, flavoring every sensation with delicious pleasure. Then it doubled in intensity, then doubled again, and it _kept_ growing. It was as if every orgasm she’d been denied throughout her estrus had dropped on her all at once. Her mind would go blank from pure overstimulation, only to be pulled back down to reality by the incessant electric jolts of pleasure on every front.

Her stomach buckled as her abs clenched tight, forcing her to let go of her breast and vibrator to hold herself up. With both palms on the bed, she leaned forward, panting for breath, her long brunette hair falling in her face. It tickled her nose but that didn’t even register. There were dozens of other sensations fighting for her attention that were stronger by orders of magnitude.

Not the strongest sensation by a longshot, but the most in her control, was the vibrator currently wedged all the way into her front pussy and cranked to max settings. Part of her wanted to turn it off, to get it out and silence at least one of the many tantalizing torturers that were battering her frazzled nervous system. But another part of her wanted to cram that vibrator in harder, to grind on it and keep this tsunami of stimulation going forever. That part won out, at least temporarily.

Serah fell further forward until her upper body was propped up on her right forearm and elbow, then she maneuvered her left hand back between her front legs. She’d thought that the vibrator was as far in as it could go, pressed by the bed and her body, but it turns out there was a bit of leeway yet. She slipped her hand under it, palm up, then lifted it with three fingers. It contacted two points simultaneously: her clitoris, via the external ‘rabbit’ part of the vibrator, and her cervix, which had been pushed down closer by her crunched position.

While some women found even the slightest contact on their cervix uncomfortable or even painful, other women found it pleasurable. Serah was very much in the second camp. She loved vibrations deep inside herself, directly on her cervix, even if it usually meant soreness for a day or two afterwards. In her current state of continuous orgasm, that direct contact was beyond her expectations.

The instant the vibrator touched that bundle of nerves at the entrance to her womb, they went wild. Her stomach clenched tighter, her front legs spasmed, and her breath caught in her throat. She moaned into the bedspread, then bit it in her teeth while she rode out the never ending hurricane of orgasmic bliss.

Meanwhile, Shoto was running out of steam. Weeks of twice-daily (or more) sex had taken a lot out of him physically and everything about the stressful estrus situation had taken a toll on his mental state. His dick was still hard enough to thrust into Serah's ass, dragging a ballooned condom along with it, but his hips were screaming with an aching pain and his thighs were starting to cramp.

“I’m sorry, Serah, but I’m done,” he said as he fell backward onto his heels, pulling out on the way. The very full condom was thankfully still in place so he went to reach for a tissue to clean up, but he stopped partway.

Before him was a frantically orgasming woman, her vibrator-stuffed pussy on broad display. He quickly discovered that while his body was no longer capable of sex, his mind was still very much willing. He got hard again, painfully so, but finished getting a tissue to throw the condom away. After that was done, he laid on his side and propped his head up with one arm, and quietly watched his lovely girlfriend experiencing pure bliss.

Thirty seconds, then a minute, then two; Serah just kept cumming. While she had needed anal sex to get the party started, now that the doors were open, the two vibrators were more than enough to keep the celebration rolling. Like a burst dam letting loose its entire contents, there was no stopping the wave after wave of orgasms crashing upon her. Shoto sat back and enjoyed the show as a passive audience, but Serah was smack in the middle of it.

On some level she knew Shoto had pulled out. Fainter still she thought he was watching her, but she was lost in the physical sensation of yet another orgasm. That was assuming that it even _was_ a different orgasm. She couldn’t know for sure where one ended and the next began. All she did know is that she was approaching her limits, both mentally and physically.

Her horse parts seemed to have a higher tolerance than her human ones and soon her front pussy was getting twitchy and irritated from overstimulation. With the last of her conscious effort, she flipped that vibrator off. Then, with it and the active Big One still in her, she flopped forward and passed out, her lower body still upright and her ass still in the air.

“Uh, Serah?” Shoto called out. At first, he thought it was just another step on her orgasmic journey but he quickly realized she was asleep. “I should turn the Big One off,” he mumbled to himself as he looked for the remote. It was nowhere in sight so he guessed it was stuck under Serah somewhere, or tossed away in a moment of ecstasy.

Rather than keep searching fruitlessly, he reluctantly rose from the bed. His hip joints cried rebelliously as he walked over and unplugged the toy from the wall entirely. The Big One rumbled to a stop and the room became eerily silent. He’d grown used to the low buzz of both vibrators and the rapid breathing of two lovers in action, not to mention the wet slapping of body on body. But now the only sound was the slow breath of his sleeping darling.

_Should I take it out of her?_ he wondered. _It might be bad to stay stretched out for too long, and her body needs to recover, I think._ With that decided, Shoto grabbed the hefty base of the toy and tugged. Because of the tapered effect near the base, it took an unexpected amount of force to get the large dildo free of her clasping vagina. But he managed.

It popped loose with a lewd _SLUPP_ and a flood of juices followed after, soaking the intelligently placed towel below Serah's hindquarters. Shoto found his gaze entranced by the sight of Serah's gaping pussy, which was slowly contracting again. Even as it closed, it would easily fit his hand. His penis would have barely registered inside it.

He felt a twinge of sorrow that he would never be able to satisfy that hole, but it faded when he remembered that she had _two_ others that were much better fits. With that wholesome thought, Shoto continued to tend to his sleeping girlfriend, tipping her on her side to get the other dildo out of her. He wiped up some messes, then snuggled up next to her.

They’d both need to get cleaned up properly eventually, but for now he was content to savor the calm moment.


End file.
